The invention relates to a method for establishing telecommunications links in a switching system, in particular in a mobile communications system, having a plurality of base stations. Each of the base stations has a plurality of transmitting/receiving devices which are assigned to a plurality of terminals. The invention further relates to a switching system for establishing telecommunications links.
Methods and switching systems for establishing telecommunications links, in particular mobile communications systems having a plurality of base stations, are known. In mobile communications systems, a base station has a plurality of transmitting/receiving devices. These transmitting/receiving devices are assigned a plurality of terminals in such a way that each of the transmitting/receiving devices transmits useful information and/or signaling information to all the terminals to which a telecommunications link is to be established or to which a telecommunications link has already been established. In this case, useful information and/or signaling information is transmitted in a time-shifted manner and at transmission frequencies which are specific to the transmitting/receiving device, between the transmitting/receiving devices of in each case one base station and associated terminals.
The prior art systems have the disadvantage that the number of terminals to which telecommunications links can be established is limited by the number of transmitting/receiving devices in a base station, and by the number of different frequencies. Thus, in the prior art systems, telecommunications links can be established at most to a number of terminals which is equal to the number of transmitting/receiving devices.
It is accordingly an object of the invention to provide a method for establishing telecommunications links and a corresponding switching system which overcome the above-mentioned disadvantages of the heretofore-known methods and systems of this general type and which provide improved transmission capabilities.
With the foregoing and other objects in view there is provided, in accordance with the invention, a method for establishing telecommunications links in a switching system, in particular in a mobile communications system. The method comprises the steps of providing a first number of terminal devices; providing a base station having a second number of transmitting/receiving devices assigned to the terminal devices, the first number being greater than the second number; transmitting a useful information and/or a signaling information at different times and using a redundant coding, from a transmitting/receiving device of the second number of transmitting/receiving devices to a given terminal device of the first number of terminal devices in a first transmission cycle in time with at least one transmission frequency of a plurality of transmission frequencies specific to the transmitting/receiving devices; subsequently interrupting a transmission from the transmitting/receiving device to the given terminal device for a time period equivalent to a transmission period of at least one of the plurality of transmission frequencies; and continuing the transmission from the transmitting/receiving device to the given terminal device in a second transmission cycle in time after the time period has elapsed.
In accordance with another mode of the invention, at least one of the useful information and the signaling information is transmitted from the transmitting/receiving devices of the base station to the terminal devices with only a part of the plurality of transmission frequencies being specific to the transmitting/receiving devices and being available to the terminal devices.
In accordance with yet another mode of the invention, at least one of the useful information and the signaling information is transmitted with at least one of the transmitting/receiving devices, the at least one of the transmitting/ receiving devices using more than one transmission frequency of the plurality of transmission frequencies.
In accordance with a further mode of the invention, it is provided to transmit, with the given terminal device, at least one of the useful information and the signaling information with at least the one transmission frequency of the plurality of transmission frequencies in the time period in which the transmission from the transmitting/receiving device to the given terminal device is interrupted.
In accordance with another mode of the invention, a transmission from the given terminal device is interrupted in the time period in which the transmission from the transmitting/receiving device to the given terminal device is interrupted.
In accordance with yet another mode of the invention, a receive operation of the given terminal device is switched off in the time period in which the transmission from the transmitting/receiving device to the given terminal device is interrupted.
In accordance with another mode of the invention, there is, from at least one of the transmitting/receiving devices to the given terminal device, a transmission of information for designating at least one of the plurality of transmission frequencies to be used or not to be used by the given terminal device.
In accordance with another mode of the invention, it is provided to transmit, from at least one of the transmitting/receiving devices to the given terminal device, information for designating a time for transmitting at least one of the useful information and the signaling information with the given terminal device or information for designating a time for interrupting a transmission from the given terminal device.
In accordance with another mode of the invention, from at least one of the transmitting/receiving devices to the given terminal device, information is transmitted for designating a time at which the given terminal device is switched to receive or is switched not to receive.
In accordance with a further mode of the invention, a quality of a transmission is checked of the useful information and/or signaling information transmitted from one of the transmitting/receiving devices to one of the terminal devices; and the time period in which the transmission of at least one of the useful information and the signaling information from the transmitting/receiving device to the given terminal device is interrupted is reduced, if the quality of the transmission is less than a given threshold value.
With the objects of the invention in view there is also provided, a method for establishing telecommunications links in a switching system, in particular in a mobile communications system, which comprises the steps of selecting transmission frequencies from a range of transmission frequencies, by cyclically or pseudo-randomly assigning, in a first selection process, the transmission frequencies to different base stations, and, in a second selection process within a respective one of the base stations, cyclically or pseudo-randomly assigning the transmission frequencies to terminal devices assigned to the respective one of the base stations; and transmitting a useful information and/or a signaling information between transmitting/receiving devices of the respective one of the base stations and the terminal devices assigned to the respective one of the base stations with the selected transmission frequencies.
In accordance with another mode of the invention, the second selection process includes using different selection algorithms and preferably uncorrelated selection algorithms in the different base stations.
In accordance with yet another mode of the invention, from the transmitting/receiving devices to at least one of the terminal devices, information is transmitted for designating parameters for the first and second selection processes.
With the objects of the invention in view there is also provided, a switching system for establishing telecommunications links, comprising a first number of terminal devices; a base station having a second number of transmitting/ receiving devices assigned to the terminal devices, the first number being greater than the second number; a control unit connected to the base station and programmed to perform in combination with the base station and the terminal devices the steps of transmitting a useful information and/or a signaling information at different times and using a redundant coding, from a transmitting/receiving device of the transmitting/receiving devices to a given terminal device of the terminal devices in a first transmission cycle in time with at least one transmission frequency of a plurality of transmission frequencies specific to the transmitting/receiving devices; subsequently interrupting a transmission from the transmitting/receiving device to the given terminal device for a time period equivalent to a transmission period of at least one of the plurality of transmission frequencies; and continuing the transmission with the transmitting/receiving device to the given terminal device in a second transmission cycle in time after the time period has elapsed.
With the objects of the invention in view there is further provided, a switching system for establishing telecommunications links, comprising a plurality of base stations each of the base stations having transmitting/receiving devices; a plurality of terminal devices assigned to the base stations; a control unit connected to the base stations and programmed to perform in combination with the base stations the steps of selecting transmission frequencies from a range of transmission frequencies, by cyclically or pseudo-randomly assigning, in a first selection process, the transmission frequencies to the base stations, and, in a second selection process within a respective one of the base stations, cyclically or pseudo-randomly assigning the transmission frequencies to the terminal devices assigned to the respective one of the base stations; and transmitting a useful information and/or a signaling information between the transmitting/receiving devices of the respective one of the base stations and the terminal devices assigned to the respective one of the base stations with the selected transmission frequencies.
The invention has a number of advantages, in particular, the invention increases the number of terminals to which telecommunications links can be established from the respective base station, and from which telecommunications links can be established to the associated base station. The number of costly transmitting/receiving devices in the base stations remains unchanged, so that telecommunications links to a greater number of terminals can thus be established with the same number of transmitting/receiving devices per base station. A further advantage of the invention is that there is no need to change the specification of the base stations or of the transmitting/receiving devices. Furthermore, there is no need to change the terminals or mobile stations either.
The invention also provides, in a first selection process, for the transmission frequencies to be assigned to different base stations cyclically or pseudo-randomly, and, in a second selection process, for the transmission frequencies to be assigned to the associated terminals cyclically or pseudo-randomly within a base station. This has the advantage that a single terminal is assigned a relatively large number of frequencies, and any interference which may possibly occur is thus distributed.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a method and a switching system for establishing telecommunications links, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.